sentence='hello world'
center_str=sentence.center(13,'-')
ljust_str=sentence.ljust(13,'*')
rjust_str=sentence.rjust(13,'%')
print(f"居中显示：{center_str}")
print(f"左对齐显示：{ljust_str}")
print(f"右对齐显示：{rjust_str}")